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US 2014/0176006 A1Published application
Display panel
AssigneeGlobal OLED Technology LLC
InventorKazuyoshi Kawabe
Life of this patent
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Abstract
An EL light-emitting element is driven digitally to reduce power consumption using a pixel having three transistors and two capacitors. A reset transistor for diode connection writes the threshold voltage of the drive transistor onto a coupling capacitor. The data voltage plus threshold voltage is then written onto the gate of the drive transistor. This reduces the amplitude of the data voltage required, further reducing power consumption.
Claims3
A display pixel, comprising:
- (a) a coupling capacitor having a first terminal connected directly to a data line;
- (b) a selection transistor having a first terminal connected to a second terminal of the coupling capacitor, and a gate connected to a selection line;
- (c) a driving transistor having a first terminal connected to a power source and a gate connected to a second terminal of the selection transistor, wherein the driving transistor supplies a current from the power source in accordance with a gate potential;
- (d) a light emitting element connected to a second terminal of the driving transistor and emitting light as a result of the current supplied by the power source through the driving transistor;
- (e) a reset transistor having a first terminal connected to the second terminal of the driving transistor;
- a second terminal connected to the first terminal of the selection transistor;
- and a gate connected to a reset line;
- and
- (f) a storage capacitor connected between the gate of the driving transistor and the power source.
6 more elements
A method for supplying current to a light-emitting element in a display pixel, comprising:
- (a) providing a data line, a selection line, a power source and a reset line;
- (b) providing the display pixel having:
- (i) a coupling capacitor having a first terminal connected directly to the data line;
- (ii) a selection transistor having a first terminal connected to a second terminal of the coupling capacitor, and a gate connected to the selection line;
- (iii) a driving transistor having a first terminal connected to the power source and a gate connected to a second terminal of the selection transistor, wherein the driving transistor supplies a current from the power source in accordance with a gate potential;
- (iv) the light-emitting element connected to a second terminal of the driving transistor and emitting light as a result of the current supplied by the power source through the driving transistor;
- (v) a reset transistor having a first terminal connected to the second terminal of the driving transistor;
- a second terminal connected to the first terminal of the selection transistor;
- and a gate connected to the reset line;
- and
- (vi) a storage capacitor connected between the gate of the driving transistor and the power source for storing the gate potential;
- (c) providing a data driver for providing a data signal to the data line;
- (d) providing a gate and reset driver for providing respective voltages to the selection line and the reset line;
- (e) performing in order the following steps:
- (i) providing a pre-charge potential on the data line;
- (ii) turning on the selection transistor and the reset transistor to write a reset potential into the coupling capacitor;
- (iii) turning off the selection transistor and the reset transistor;
- (iv) providing a data potential on the data line;
- and
- (v) turning on the selection transistor to write the gate potential corresponding to the reset potential and the data potential into the storage capacitor, whereby the driving transistor supplies current from the power source to the light-emitting element.
17 more elements
Dependencies are inferred from the claim text.